1. Field of the Invention
This invention relates generally to arrangements for holding work pieces at predetermined or convenient orientations, and more particularly, to an arrangement that allows simultaneous locking in place and clamping of a work holder arrangement at a precise location and orientation, and with multiple degrees of freedom with infinite resolution.
2. Description of the Related Art
Support arms for work holder arrangements are used in the prior art in various ways, such as for preparing sheet metal parts for assembly or further production. Often, such arrangements are employed with a holding arrangement that includes a suction cup, and are used to carry articles from one production process to another, or to hold the articles during processing.
It is desired to provide a mounting bracket, or arm, that affords quick orientation and clamping of the bracket into a desired position, while also permitting infinite resolution over multiple degrees of freedom. Some prior art work holder arrangements achieve rapid clamping and setting with a single fastener. These known brackets, however, achieve the clamping convenience at the expense of degrees for freedom. For example, a known bracket that clamps and sets with a single fastener provides neither axial extension of the bracket nor rotational positioning about the axis. This known bracket, therefore, is not universal.
Similarly, a further known bracket that has endeavored to achieve the capacity for rotational positioning about the axis requires that fixation be effected only at predetermined increments of rotation. This known arrangement does not provide infinite rotational placement resolution, and provides no axial extension whatsoever.
It is, therefore, an object of this invention to provide a mounting bracket arrangement for a work piece in process that provides rotational and axial placement about the bracket axis.
It is another object of this invention to provide a mounting bracket arrangement for a work piece in process that provides infinite placement resolution in rotational and axial placement of the work piece with respect to the bracket axis.
It is also an object of this invention to provide a mounting bracket arrangement for a work piece in process that provides up to four degrees of freedom of placement of the workpiece with respect to a mounting structure.
The foregoing and other objects are achieved by this invention which provides, in accordance with a first apparatus aspect thereof, a work holder arrangement for supporting a work article at a desired orientation with respect to a support structure. The work holder arrangement is provided with a first clamp member for coupling with the support structure, the first clamp member having clamped and unclamped states. There is additionally a second clamp member for coupling with the work article, the second clamp member having clamped and unclamped states. A tube portion is coupled to selected one of the first and second clamp members, and a shaft portion is coupled to the other of the first and second clamp members. The shaft portion is accommodates, coaxially within the tube portion. Additionally, there is provided an expansion portion arranged coaxially with the shaft portion within the tube portion. The invention further is provided with an elongated member for engaging with the expansion portion and for applying an axial force thereto. Thus, upon the application of the axial force, the expansion portion is urged transaxially against an interior surface of the tube portion, and the selected one of the first and second clamp members simultaneously is urged into the clamped state.
In one embodiment of the invention, the expansion portion is provided with a transverse ramp portion, and the shaft portion is terminated at an end portion thereof distal from the selected one of the first and second clamp members with a corresponding transverse ramp portion. In this manner, the transverse ramp portion of the expansion portion and the corresponding transverse ramp portion of the end portion of the shaft portion are arranged to communicate with each other. The expansion portion is engaged with the elongated member, and the axial force applied thereto is responsive to a displacement of the elongated member with respect to the expansion portion. Further in accordance with this embodiment of the invention, the communication between the transverse ramp portion of the expansion portion and the corresponding transverse ramp portion of the end portion of the shaft portion precludes rotation of the expansion portion as the elongated member is rotated.
Preferably, the shaft portion has a longitudinal bore therethrough for accommodating the elongated member. The longitudinal bore is axially arranged and dimensioned to accommodate a transaxial displacement of the elongated member, which occurs when the expansion portion is urged along the transverse ramp portion. In other embodiments, however, the elongated member is itself transaxially deformed, or flexed, to accommodate the transaxial displacement of the expansion portion as it is urged along the transverse ramp portion.
In a further embodiment of the invention, the shaft portion and the tube portion each have a circular cross-sectional configuration, whereby the expansion portion can be urged transaxially against an interior surface of the tube portion to fix the shaft portion at any axial location within the tube portion within a predetermined limit and at any rotational orientation between the shaft and tube portions. That is, the axial location of the shaft portion within the tube portion is adjustable with infinite resolution, as is the rotational orientation between these two portions.
In a practical application of the invention, the support structure is in the form of a support bar having a predetermined cross-sectional configuration. The first clamp member is configured to be rotatable about support bar, and slidable axially therealong, when the first clamp member is in the unclamped state. It is fixed axially and rotationally thereto when the first clamp member is in the clamped state.
In a still further embodiment of the invention, there is additionally provided a work article engagement arrangement having a predetermined configuration, and the second clamp member is correspondingly configured. The work article engagement arrangement is angularly displaceable when the second clamp member is in the unclamped state, and fixed angularly with respect thereto when the second clamp member is in the clamped state. In a practical embodiment, the work article engagement arrangement has a substantially spherical configuration and the second clamp member is correspondingly configured to have a concave configuration. The work article engagement arrangement in this embodiment is displaceable angularly with infinite resolution over a conical region. Alternatively, the work article engagement arrangement has a substantially cylindrical or somewhat concave (or apple-core-like) configuration and the second clamp member is correspondingly configured to have a substantially cylindrical internal configuration. In this substantially cylindrical embodiment of the invention, however, the work article engagement arrangement is not displaceable angularly.
In a highly advantageous embodiment of the invention, the first clamp member and the shaft portion are integrally formed with each other. The expansion portion has a cross-sectional configuration that corresponds to the cross-sectional configuration of the shaft portion. Similarly, in this advantageous embodiment, the second clamp member and the tube portion are integrally formed with each other.
The axial force applied by the elongated member urges the first clamp portion and the expansion portion toward each other.
In accordance with a further apparatus aspect of the invention, there is provided a work holder support arm for supporting a work article at a desired orientation with respect to a support structure. The work holder arrangement is provided with a first clamp member having clamped and unclamped states for coupling with the support structure. The first clamp member has an opening therethrough for accommodating the support structure, and through-hole arranged transverse to the opening. A shaft portion is coupled to the first clamp member, the shaft portion having a longitudinal bore therethrough arranged to be axially in registration with the through-hole of the first clamp member. Additionally, there is provided a second clamp member for coupling with the work article, the second clamp member having clamped and unclamped states. A tube portion is coupled to the second clamp member for accommodating telescopically therewithin the first shaft portion. An expansion portion is arranged coaxially with the shaft portion within the tube portion, and is provided with a threaded section. An elongated member with a threaded portion for engaging with the threaded section of the expansion portion is provided for applying an axial force thereto. Upon the application of the axial force, the expansion portion is urged transaxially against an interior surface of the tube portion, and simultaneously the selected one of the first and second clamp members is urged into the clamped state.
In one embodiment of this further aspect of the invention, the first clamp member and the shaft portion are integrally formed. Similarly, the second-clamp member and the tube portion are integrally formed.
In a preferred embodiment, the expansion portion and the shaft portion have. corresponding transverse ramps arranged to communicate with each other, where by upon the application of the axial force, the expansion portion is urged along the transverse ramp of the shaft portion and substantially radially against an interior surface of the tube portion
As previously noted, a work article engagement arrangement has a predetermined configuration, and the second clamp member is correspondingly configured. Thus, the work article engagement arrangement is angularly displaceable when the second clamp member is in the unclamped state, and fixed angularly with respect thereto when the second clamp member is in the clamped state. The work article engagement arrangement is in this embodiment, displaceable with infinite resolution over a conical region.